Meaning

noun the syllable naming the second (supertonic) note of any major scale in solmization

noun a widely distributed system consisting of all the cells able to ingest bacteria or colloidal particles etc, except for certain white blood cells

noun a rare heavy polyvalent metallic element that resembles manganese chemically and is used in some alloys; is obtained as a by-product in refining molybdenum

originFrom re + -s.

Etymology from Wiktionary, CC BY-SA 3.0